Vehicle-use electronic key system

ABSTRACT

A vehicle-use electronic key system includes a control unit mounted on a real car, and an electronic key for sending a response signal on receiving a request signal sent from the control unit via a transmission antenna, the antenna being installed near the middle of the real car. Specifically, when a line segment (wheel base) connecting the center of a front wheel to the center of a rear wheel is assumed, the transmission antenna is installed in any location within a range from the upper part to the lower part of the real car within a range from a ¼ point to a ¾ point of the wheel base with the center of the front wheel as a reference.

TECHNICAL FIELD

This invention relates to an electronic key system for a vehicle whereinradio communication is performed between a transmitter/receiver(electronic key) carried by a user and a control apparatus mounted on anactual vehicle to verify an ID and, if a request received originatesfrom a legal user, then starting of an engine or some other action isperformed, and more particularly to an electronic key system for avehicle suitable for use with, for example, a motorcycle.

BACKGROUND ART

An electronic key system for a vehicle is disclosed, for example, inJapanese Laid-Open Patent Publication No. 2001-349110 and JapaneseLaid-Open Patent Publication No. 2001-349117. In the electronic keysystem for a vehicle disclosed in Japanese Laid-Open Patent PublicationNo. 2001-349110 and Japanese Laid-Open Patent Publication No.2001-349117, starting means (switches) are provided on a door handle anda trunk lid of an actual vehicle. If a user operates (starts) any of thestarting means, then communication of a control apparatus with anelectronic key is started. Then, the control apparatus verifies an IDtransmitted thereto from the electronic key with an ID registeredtherein. Thus, if a result of the verifying that the IDs are coincidentwith each other is obtained, then door locking and so forth arecancelled.

Further, in Japanese Laid-Open Patent Publication No. 2001-349110 andJapanese Laid-Open Patent Publication No. 2001-349117 described above, astarting means (switch) is provided also on an ignition knob. If theuser operates the ignition knob after the user gets on the four-wheeledcar, then the communication between the electronic key and the startingmeans is performed again to perform ID verifying for permitting startingof the engine. Then, if a result of the verifying that the IDs arecoincident with each other, the engine is started.

In particular, in the conventional vehicle electronic key system for afour-wheeled car, the electronic key has a function for unlocking a doorand a function for permitting starting of an engine.

Further, as a different prior art apparatus, an electronic key system isproposed (refer to, for example, Japanese Laid-Open Patent PublicationNo. 10-317754) wherein transmitting antennas are provided individuallyfor doors of a four wheeled car, and only that one of the doors which isapproached by a portable device can be unlocked independently of theother doors of the vehicle.

In this manner, in the electronic key system described above, the rangeof transmitting from the control apparatus mounted on an actual vehiclein the communication between the control apparatus and the electronickey is small in comparison with that from the electronic key. Therefore,in the prior art apparatus described above, a plurality of transmittingantennas for outputting a signal from the control apparatus are provideddepending upon different applications.

Incidentally, in order to apply such an electronic key system to amotorcycle, at least when a user gets on and operates the actual vehicleand when the user is running with the actual vehicle, it is necessaryfor the user to communicate with certainty with the electronic keycarried by the user.

Particularly in a motorcycle such as a scooter wherein a helmet can beaccommodated in a space provided under a seat, it is necessary toperform communication of the control apparatus with the electronic keywith certainty. This applies not only when the user gets on and operatesthe actual vehicle and when the user is running with the actual vehicle,but also upon opening or closing operation of the seat and when theelectronic key is accommodated in the helmet accommodating space.

Particularly where the vehicle is a motorcycle of a large size, in orderto achieve communication of the control apparatus with the electronickey in all of the situations described above, it is necessary to installa plurality of transmitting antennas at different locations such as afront portion and a rear portion of the actual vehicle. This maypossibly invite increase of the cost and the weight of the electronickey system and the installation space for the electronic key system.

In a motorcycle such as a scooter wherein a helmet can be accommodatedin a space provided under a seat, such a method as described below isavailable. In particular, a locking mechanism for locking anopening/closing mechanism of a seat is provided, for example, for theobject of antitheft. Thus, if a legal user is recognized throughcommunication of a control apparatus with an electronic key, then thelocked state of the seat is released.

In such a case as just described, such a manner of use is possible thatan electronic key placed in a bag or the like is accommodated in ahelmet accommodating space. In such a manner of use as just described,if communication between the control apparatus and the electronic key isinterrupted, then there is the possibility that the locked state of theseat cannot be released, that is, shut-in of a baggage may occur.

DISCLOSURE OF THE INVENTION

The present invention has been made in such a subject as describedabove, and it is an object of the present invention to provide anelectronic key system for a vehicle by which communication of a controlapparatus with an electronic key in all of the situations describedabove can be achieved without inviting increase of the cost and theweight, increase of the installation space and so forth.

Another object of the present invention to provide an electronic keysystem for a vehicle wherein, even if an electronic key is placed in ahelmet accommodating space, communication of the control apparatus withthe electronic key can be performed with certainty and a so-calledshut-in state of a baggage and so forth can be prevented.

According to the present invention, an electronic key system for avehicle which includes a control apparatus mounted on an actual vehicleand an electronic key for transmitting a response signal in response toreceiving of a request signal transmitted from the control apparatusthrough a transmitting antenna is characterized in that the transmittingantenna is installed in the proximity of the center of the actualvehicle.

Consequently, a request signal transmitted from the control apparatus isoutputted from the location in the proximity of the actual vehicle.Therefore, as the transmitting range, an almost entire region of theactual vehicle can be covered. As a result, communication of the controlapparatus with the electronic key can be performed with certainty whenthe user gets on and operates the actual vehicle, when the user isrunning with the actual vehicle, upon opening or closing operation ofthe seat and when the electronic key is accommodated in a helmetaccommodating space. In this instance, since a single transmittingantenna may be installed, communication of the control apparatus withthe electronic key in all of the situations described above can beachieved without inviting increase of the cost and the weight, increaseof the installation space and so forth.

Preferably, the transmitting antenna is installed at a position within arange from an upper portion to a lower portion within a range from apoint at one fourth to another point at three fourths of a wheel basewith reference to the center of a front wheel of the actual vehicle.

Particularly where the actual vehicle includes a seat on which a user isto be seated, preferably the transmitting antenna is installed in theproximity of a front portion of the seat.

According to the present invention, an electronic key system for avehicle which includes a control apparatus mounted on an actual vehicleand an electronic key for transmitting a response signal in response toreceiving of a request signal transmitted from the control apparatusthrough a transmitting antenna, characterized in that the actual vehicleincludes a seat provided for opening and closing movement for beingseated by a user and a locking apparatus for locking the seat so as notto be opened until unlocking instruction is supplied thereto, that thecontrol apparatus includes means for verifying the response signal andoutputting an unlocking instruction to the locking apparatus when it isdiscriminated that the response signal is a request from a legal user,and that the transmitting antenna is installed on the seat or in theproximity of the seat.

Consequently, a request signal transmitted from the control apparatus isoutputted from the seat or a position in the proximity of the seat.Therefore, as the transmitting range, the seat and a region around theseat can be covered. As a result, even if the electronic key is shut ina helmet accommodating space, communication of the control apparatuswith the electronic key can be performed with certainty and a so-calledshut-in state of a baggage or the like can be avoided.

The transmitting antenna may be provided on a left side face of theseat. Normally, the user operates the seat to open or close standing onthe left side of the actual vehicle. Therefore, by mounting thetransmitting antenna on the left side face of the seat, communication ofthe control apparatus with the electronic key can be performed withcertainty.

Where at least a seat handle which is used to open or close the seat bymanual operation is provided around a rear portion of the seat, thetransmitting antenna may be provided on the seat handle.

Normally, the seat handle can be assembled later to a vehicle body ofthe actual vehicle. Therefore, the shape of the vehicle body or the pathof wiring lines need not be changed significantly in order to providethe transmitting antenna. In other words, the transmitting antenna canbe mounted with a slight design change, and also the cost can be reducedadvantageously.

The above and other objects features and advantages of the presentinvention will become more apparent from the following description whentaken in conjunction with the accompanying drawings in which a preferredembodiment of the present invention is shown by way of illustrativeexample.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing an electronic key system according toa first embodiment and a second embodiment.

FIG. 2 is a block diagram showing a configuration of an electronic key.

FIG. 3 is a block diagram showing a configuration of a controlapparatus.

FIG. 4 is a schematic view showing an example of operation switches(switches which may be listed as a candidate of a starting switch)around a handle bar on an actual vehicle of the motorcycle type.

FIG. 5 is a schematic view showing an example of operation switches(switches which may be listed as a candidate of a starting switch)around a handle bar on another actual vehicle of the scooter type.

FIG. 6 is a schematic view showing an example wherein a starting switchis installed in the proximity of a seat on an actual vehicle of thescooter type which is used by the first embodiment.

FIG. 7A is a side elevational view showing an example of a location of atransmitting antenna on an actual vehicle (See FIG. 6).

FIG. 7B is a plan view of the same.

FIG. 8 is a schematic view showing an example wherein a starting switchand a transmitting antenna are provided on a seat or a seat handle on anactual vehicle of the scooter type which is used by the secondembodiment.

FIG. 9 is an enlarged view showing a state wherein a seat is opened.

FIG. 10 is a side elevational view showing an example of a position atwhich a transmitting antenna is installed on an actual vehicle.

FIG. 11 is a top plan view showing the example of the position at whichthe transmitting antenna is installed on the actual vehicle.

FIGS. 12A to 12E are timing charts illustrating processing operation ofthe electronic key system according to the present embodiment.

FIG. 13 is a schematic view showing an example wherein a transmittingunit of an electronic key system according to a third embodiment ismounted on an actual vehicle.

FIG. 14 is a schematic view showing an example wherein a transmittingunit of an electronic key system according to a fourth embodiment ismounted on an actual vehicle.

FIG. 15 is a block diagram showing a configuration of a controlapparatus and the transmitting unit in the electronic key systemaccording to the third embodiment and the fourth embodiment.

FIG. 16 is a schematic view showing an example wherein atransmitting/receiving unit of an electronic key system according to afifth embodiment is mounted on an actual vehicle.

FIG. 17 is a schematic view showing an example wherein atransmitting/receiving unit of an electronic key system according to asixth embodiment is mounted on an actual vehicle.

FIG. 18 is a block diagram showing a configuration of a controlapparatus and the transmitting/receiving unit of the electronic keysystem according to the fifth embodiment and the sixth embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, an embodiment wherein an electronic key system for avehicle according to the present invention is applied, for example, to asystem of a motorcycle is described with reference to FIGS. 1 to 18.

Referring to FIG. 1, Each of electronic key systems 10A, 10B accordingto a first and a second embodiments includes an electronic key 12 forbeing carried by a user and a control apparatus 14 mounted on an actualvehicle 100A (refer to FIG. 6) and an actual vehicle 100B (refer to FIG.8). As the electronic key 12, a key which has a shape of a key as anouter shape thereof and incorporates an IC chip therein, another keywhich has a shape of a card as an outer shape thereof and incorporatesan IC chip therein, and some other keys are available. Where theelectronic key system according to the present invention is principallyapplied as a key-less system, a key having a shape of a card is used. Inthe present specification described below, it is assumed that theelectronic key 12 has a shape of a card.

Referring to FIG. 2, the electronic key 12 has a shape of a card as justdescribed and includes a battery 20, a power supply circuit 22, a CPU24, a receiving circuit 26 and a transmitting circuit 28 in the insidethereof.

The power supply circuit 22 supplies power supplied from the battery 20to the receiving circuit 26, the transmitting circuit 28 and the CPU 24.The receiving circuit 26 includes a receiving antenna not shown.Further, the receiving circuit 26 receives a request signal Sr and soforth transmitted thereto from the control apparatus 14 through thereceiving antenna and extracts the signal from a carrier wave to decodethe signal. The decoded signal is supplied to the CPU 24. The frequencyof the carrier wave of the request signal Sr ranges from 100 kHz to 300kHz.

The CPU 24 executes at least two computer programs (a request signalverifying means 30 and a response signal generating means 32). Therequest signal verifying means 30 verifies whether or not a signalsupplied from the receiving circuit 26 is the request signal Sr. Thus,if the signal supplied is the request signal Sr, the request signalverifying means 30 passes the control to the response signal generatingmeans 32. The response signal generating means 32 reads out ID datarecorded in a ROM not shown based on a request from the request signalverifying means 30. Then, the response signal generating means 32 addsan attribute that indicates a response to the ID data and outputs the IDdata as transmitting data Dt to the transmitting circuit 28. Thetransmitting circuit 28 includes a transmitting antenna not shown. Thetransmitting circuit 28 modulates a carrier wave in accordance with thetransmitting data Dt supplied from the CPU 24 and transmits themodulated wave as a response signal Sa through the transmitting antenna.The frequency of the carrier wave of the response signal Sa ranges from200 MHz to 500 MHz.

Meanwhile, the control apparatus 14 mounted on the actual vehicles 100A,100B is formed from, for example, a system LSI. Further, for example, asshown in FIG. 3, the control apparatus 14 includes a power supplycircuit 40, a CPU 42, a receiving circuit 44, a transmitting circuit 46,an inputting circuit 48, a first driving circuit 52 (for driving anactuator), a second driving circuit 54 (for driving a main relay) and athird driving circuit 56 (for driving an LED). At least a battery 60, amain switch 62, an actuator (driving source for a locking apparatus) 64,a main relay 66, a warning lamp 68 (LED), a starting switch 70 and atransmitting antenna 72 are installed around the control apparatus 14.

The main switch 62 has two fixed contacts 62 a and 62 b and a movablecontact 62 c. The fixed contact 62 a is connected to the battery 60, andthe other fixed contact 62 b is connected to the inputting circuit 48and the main relay 66.

Not only the fixed contact 62 b of the main switch 62 but also thestarting switch 70 are connected to the inputting circuit 48. An ON/OFFstate of the starting switch 70 and an ON/OFF state of the main switch62 are supplied to the CPU 42 through the inputting circuit 48.

The starting switch 70 can be set to any one of, for example, anoperation switch for starting an engine of the actual vehicles 100A,100B, an operation switch for security during driving and an operationswitch used for stopping the engine of the actual vehicles 100A, 100B.In particular, where each of the actual vehicles 100A, 100B is of themotorcycle type as shown in FIG. 4, any one of a lighting dimmer switch104, a clutch switch 106, a winker switch 108, a horn switch 110, afront brake switch 112, a hazard switch 114 and a starter switch 116which are installed around a handle bar 102 can be set as the startingswitch 70.

On the other hand, where each of the actual vehicles 100A, 100B is ofthe scooter type as shown in FIG. 5, any one of a lighting dimmer switch122, a rear brake switch 124, a winker switch 126, a horn switch 128, afront brake switch 130, a hazard switch 132 and a starter switch 134which are installed around a handle bar 120 can be set as the startingswitch 70.

For the setting of the starting switch 70, a method is availablewherein, for example, when a user purchases the actual vehicles 100A or100B, the user decides the setting of the starting switch 70 uponcontract with a dealer, and thereafter, wiring is performed in a factorybased on the decision. In particular, for example, wiring forinterconnection between a switch decided as the starting switch 70 andthe inputting circuit 48 of the control apparatus 14 or a like operationis performed in a factory.

As described above, the starting switch 70 may be set to any one ofvarious switches installed around the handle bar 102 or 120. Forexample, in a scooter, as shown in FIG. 6, the starting switch 70 may beprovided on the seat 140 or in the proximity of the seat 140.

A space 142 (helmet accommodating space) which can accommodate a helmetnot shown is provided under the seat 140 as shown in FIG. 9. Normally,when the user does not ride the vehicle, a helmet is accommodated in thespace. Further, depending upon the user, a baggage such as a bag may beaccommodated in the space 142.

Further, at least a handle 144 (hereinafter referred to as seat handle144 for the distinction from the handle bar 120 which is operated by adriver) used to open or close the seat 140 by manual operation isprovided around a rear portion of the seat 140.

Accordingly, as a location for the starting switch 70, the seat handle144, the inside of the seat 140 or the like is available. Where thestarting switch 70 is provided on the seat handle 144, preferably thestarting switch 70 is provided at a portion of the seat handle 144 whichis to be gripped with a hand when the user opens the seat 140. On theother hand, where the starting switch 70 is provided in the inside ofthe seat 140, preferably the starting switch 70 is buried at a locationcorresponding to a portion of the seat 140 with which the user toucheswhen the user opens the seat 140.

Consequently, if the user performs an operation to open the seat 140 inorder to take out the helmet, then the starting switch 70 is operatedinto an ON state at the same time. As a result, the operabilityregarding starting of the electronic key system 10 can be improved.

Meanwhile, the power supply circuit 40 of the control apparatus 14supplies power from the battery 60 to the CPU 42, receiving circuit 44,transmitting circuit 46 and other components.

The receiving circuit 44 has a receiving antenna not shown. Thereceiving circuit 44 receives a response signal Sa and so forthtransmitted thereto from the electronic key 12 through the receivingantenna, extracts the response signal Sa from the carrier wave anddemodulates the response signal Sa. The demodulated signal is suppliedto the CPU 42.

The CPU 42 executes at least four programs (a request signal generatingmeans 80, a request signal verifying means 82, an observing means 84 anda peripheral instruction means 86).

The request signal generating means 80 reads out request data Dr (dataon which a request signal Sr is to be based) from a ROM not shown inresponse to an ON operation of the starting switch 70 or the main switch62 and outputs the request data Dr to the transmitting circuit 46.Further, after the engine is started, the request signal generatingmeans 80 reads out the request data Dr from the ROM after every fixedinterval of time and outputs the request data Dr to the transmittingcircuit 46. The fixed interval of time is set to one of time periods of10 to 100 sec taking the consumption of the battery 20 in the electronickey 12 into consideration.

The transmitting circuit 46 modulates the carrier wave based on therequest data Dr supplied thereto from the CPU 42 and outputs a resultingsignal as a request signal Sr through the transmitting antenna 72.

In the actual vehicle 100A of the first embodiment 10A, as shown in FIG.6, the transmitting antenna 72 is installed in the proximity of thecenter of the actual vehicle 100A. As shown in FIGS. 7A and 7B, thetransmitting range of the request signal Sr is a spherical range of aradius of 1 to 1.5 m around the transmitting antenna 72 mounted on theactual vehicle 100A (a range indicated by a circle A in FIGS. 7A and7B). The transmitting range of the request signal Sr is smaller than thetransmitting range of the response signal Sa (range of a radius ofseveral meters around the electronic key 12).

Accordingly, where it is assumed that the actual vehicle 100A is ascooter wherein a helmet accommodating space not shown is installed, forexample, under the seat 140 as shown in FIGS. 7A and 7B, communicationof the control apparatus with the electronic key 12 can be carried bythe user may be performed with certainty when the user gets on andoperates the actual vehicle 100A, when the user performs an operation toopen the seat 140, when the user is running with the actual vehicle100A, when the electronic key 12 is accommodated in the helmetaccommodating space, and in any other case.

Here, a line segment (wheel base) 154 interconnecting the center 150 aof a front wheel 150 and the center 152 a of a rear wheel 152 isassumed. In this instance, a location in the proximity of the actualvehicle 100A is, for example, a position within a range from an upperportion to a lower portion of the actual vehicle 100A within a rangefrom a point P1 at one fourth to another point P2 at three fourths thewheel base 154 with reference to the center 150 a of the front wheel150. In the actual vehicle 100A, the transmitting antenna 72 isinstalled in the proximity of a front portion of the seat 140.

Meanwhile, In the actual vehicle 100B of the second embodiment 10B, asshown in FIG. 8, the transmitting antenna 72 is installed on the seat140 of the actual vehicle 100B or in the proximity of the seat 140. Asshown in FIGS. 10 and 11, the transmitting range of the request signalSr is a spherical range of a radius of 1 to 1.5 m around thetransmitting antenna 72 mounted on the actual vehicle 100B (a rangeindicated by a circle A in FIGS. 10 and 11). The transmitting range ofthe request signal Sr is smaller than the transmitting range of theresponse signal Sa (range of a radius of several meters around theelectronic key 12).

Accordingly, where it is assumed that the actual vehicle 100B is ascooter wherein the helmet accommodating space 142 (refer to FIG. 9) isinstalled, for example, under the seat 140 as shown in FIGS. 10 and 11,communication of the control apparatus 14 with the electronic key 12 canbe carried by the user may be performed with certainty when the userperforms an operation to open the seat 140, when the electronic key 12is accommodated in the helmet accommodating space 142, and in some othercase.

In FIGS. 10, 11 and 8, an example is shown wherein the transmittingantenna 72 is installed at a portion of a left side face of a rearportion of the seat 140 with which the user does not touch with itshand.

Alternatively, where the seat handle 144 is provided around a rearportion of the seat 140 as seen in FIG. 9, the transmitting antenna 72is installed on the seat handle 144. Also in this instance, preferablythe transmitting antenna 72 is installed at a portion with which theuser does not normally touch with its hand.

The request signal verifying means 82 verifies whether or not a signalsupplied thereto from the receiving circuit 44 is a response signal Sa.Further, when the signal mentioned is a response signal Sa, the requestsignal verifying means 82 verifies whether or not ID data included inthe response signal Sa coincides with ID data registered in a memory notshown.

The observing means 84 observes based on an output of a request signalSr whether or not a response signal Sa is terminated (whether or notcoincidence of the ID is detected by the request signal verifying means82). The observing means 84 enters a waiting state for an input of aresponse signal Sa at a point of time when the request signal generatingmeans 80 outputs request data Dr. If a response signal Sa is notterminated within a predetermined period of time (when coincidence ofthe ID is not detected by the request signal verifying means 82), thenthe observing means 84 increments the count value by +1 to update it.Then, at a point of time when the count value becomes higher than apredetermined value, the observing means 84 outputs a warning signal Seto the third driving circuit 56.

Particularly if a response signal Sa is not terminated within thepredetermined period of time after the point of time when the requestdata Dr is outputted in response to an ON operation of the startingswitch 70 or the main switch 62, then at this stage, the observing means84 outputs a warning signal Se to the third driving circuit 56.

The observing means 84 activates the peripheral instruction means 86 ifa response signal Sa is terminated within the predetermined period oftime after the point of time at which the request data Dr is outputtedin response to an ON operation of the starting switch 70. The peripheralinstruction means 86 outputs an unlocking signal to the first drivingcircuit 52 based on a request (for unlocking) from the observing means84. Further, the peripheral instruction means 86 outputs an ON signal tothe second driving circuit 54.

The first driving circuit 52 drives the actuator 64 in response to aninput of the unlocking signal from the CPU 42 to cancel the locked stateof the handle bar 102 and the seat 104.

The second driving circuit 54 is placed into an ON state in response toan input of the ON signal from the CPU 42. Thereafter, when the mainrelay 66 is placed into an ON state in response to an ON operation ofthe main switch 62, the second driving circuit 54 starts the engine toestablish a state wherein the vehicle can run.

The third driving circuit 56 drives the warning lamp 68 in response toan input of the warning signal Se from the CPU 42 so that the warninglamp 68 emits light. For example, an LED can be used as the warning lamp68.

It is to be noted that, if the main switch 62 is operated into an OFFstate, then the main relay 66 is turned OFF and also the engine stopssimultaneously. Then, if a locking operation is performed, for example,if an operation to place the seat 104 or the seat 104 into a lockedstate is performed, then the verifying operation of the response signalSa by the control apparatus 14 is stopped. Further, the second drivingcircuit 54 is placed into an OFF state.

Now, processing operation of the electronic key system 10A according tothe first embodiment is described with reference to timing charts ofFIGS. 12A to 12E. It is to be noted that a request signal Sr is a signalhaving a pulse string based on request data Dr, and a response signal Sais a signal having a pulse string based on data including ID data. It isto be noted, however, that, in order to simplify the description, eachof the request signal Sr and the response signal Sa is represented as asignal of one pulse in FIGS. 12A to 12E. Since processing operation ofthe electronic key system 10B according to the second embodiment isalmost the same as the processing operation of the first embodiment, itomits explanation of the processing operation of the second embodiment.

First, in a normal state, if the starting switch 70 is operated to an ONstate at time t1 of FIG. 12A while the user holds the electronic key 12,then a request signal Sr is transmitted from the control apparatus 14 asseen in FIG. 12C (refer to time t2) and communication of the controlapparatus 14 with the electronic key 12 is started.

Where the user holds the electronic key 12, the request signal Sr isreceived through the receiving circuit 26 (refer to FIG. 2) of theelectronic key 12. The electronic key 12 transmits a response signal Saas seen in FIG. 12D in response to the receiving of the request signalSr (refer to time t3). The response signal Sa is supplied through thereceiving circuit 44 (refer to FIG. 3) of the control apparatus 14 tothe CPU 42, by which ID data included in the response signal Sa isverified. If it is discriminated that the ID data exhibits coincidence,then the locked state of the handle bar 120 and the seat 140 iscancelled (unlocked) as seen in FIG. 12E through the control apparatus14 and the first driving circuit 52 (refer to time t4). As a result ofthe unlocking, steering by the handle bar 120 is enabled, and the seat140 is slightly raised. Consequently, the user can recognize simply thatthe locked state of the handle bar 120 and the seat 140 has beenreleased. Further, thereupon, the second driving circuit 54 is placedinto an ON state.

Thereafter, if the user operates the main switch 62 into an ON state attime t5 of FIG. 12B while it holds the electronic key 12, then a requestsignal Sr is transmitted from the control apparatus 14 as seen in FIG.12C (refer to time t6), and communication of the control apparatus 14with the electronic key 12 is performed.

Where the user holds the electronic key 12, the electronic key 12transmits a response signal Sa as seen in FIG. 12D (refer to time t7) inresponse to the receiving of the request signal Sr in a similar manneras described hereinabove. The response signal Sa is supplied through thereceiving circuit 44 of the control apparatus 14 to the CPU 42, by whichID data included in the response signal Sa is verified. If it isdiscriminated that the ID data exhibits coincidence, then the processingadvances to a next step, that is, to a step at which the request signalSr is outputted after every interval T of time.

After this state, for example, the user is running with the actualvehicle 100A, and during the running, the request signal Sr is outputtedfrom the control apparatus 14 after every interval τ of time. In otherwords, communication of the control apparatus 14 with the electronic key12 is performed after every interval τ of time, and the electronic key12 outputs a response signal Sa after every substantially fixed intervalτ of time.

The processing operation described above is a process after the userholding the electronic key gets on and operates the actual vehicle 100Auntil it runs with the actual vehicle 100A. Now, a processing operationwhen it is detected that the electronic key 12 is absent upon startingof the actual vehicle 100A is described simply.

First, if the user operates the starting switch 70 into an ON statewhile it does not hold the electronic key 12, then a request signal Sris transmitted from the control apparatus 14. However, the controlapparatus 14 does not perform perception of a response signal Sa to therequest signal Sr outputted therefrom. As a result, the observing means84 outputs a warning signal Se to the third driving circuit 56.Consequently, the warning lamp 68 is lit. Naturally, in this instance,such a process as unlocking of the handle bar 120 and the seat 140 orthe like is not performed.

From the lighting of the warning lamp 68, the user can recognize that itdoes not hold the electronic key 12. Consequently, starting of theengine while the electronic key 12 is not held can be prevented.

Subsequently, a processing operation when it is determined that theelectronic key 12 is not present upon starting of the engine of theactual vehicle 100A is described simply.

First, if the user operates the starting switch 70 into an ON statewhile it holds the electronic key 12, then a request signal Sr istransmitted from the control apparatus 14, and communication of thecontrol apparatus 14 with the electronic key 12 is started. Through thecommunication, ID data included in a response signal is verified, and ifit is discriminated that the ID data does not exhibit coincidence, thenthe locked state of the handle bar 120 and the seat 140 is canceled.

Then, if the user operates the main switch 62 into an ON state withoutrecognizing that, for example, the electronic key 12 has dropped, thenalthough a request signal Sr is transmitted from the control apparatus14, the control apparatus 14 does not perform receiving of a responsesignal Sa to the thus outputted request signal Sr any more. As a result,the observing means 84 outputs a warning signal Se to the third drivingcircuit 56, and consequently, the warning lamp 68 is lit.

From the lighting of the warning lamp 68, the user will recognize thatthe electronic key 12 has dropped. Consequently, otherwise possible lossof the electronic key 12 can be prevented.

Now, a processing operation when it is determined that the electronickey 12 is not present while the actual vehicle 100A is running isdescribed briefly.

First, processes after an ON operation of the starting switch 70 till anON operation of the main switch 62 are same as those at times t1 to t7in FIGS. 12A to 12E.

When the engine starts in response to the ON-operation of the mainswitch 62, the processing advances to a step at which a request signalSr is outputted after every interval T of time as described hereinabove.After this stage, the user is, for example, running with the actualvehicle 100A, and during the running, a request signal Sr is outputtedfrom the control apparatus 14 after every interval τ of time.

If, for example, the electronic key 12 drops during running with theactual vehicle 100A, then receiving of a response signal Sa by thecontrol apparatus 14 is not performed any more. When a response signalSa is not received within a predetermined interval of time after thepoint of time at which the request data Dr is outputted, the observingmeans 84 increments the count value by +1 to update it. At a point oftime when the count value exceeds a predetermined value while a requestsignal Sr is successively outputted, the observing means 84 outputs awarning signal Se to the third driving circuit 56. Consequently, thewarning lamp 68 is lit.

From the lighting of the warning lamp 68, the user will recognize thatthe electronic key 12 has dropped, and otherwise possible loss of theelectronic key 12 can be prevented.

In this manner, in the electronic key system 10 according to the firstembodiment, the transmitting antenna 72 of the control apparatus 14(which transmits a request signal Sr) is installed in the proximity ofthe center of the actual vehicle 100A. Therefore, the request signal Srtransmitted from the control apparatus 14 is outputted from the locationin the proximity of the center of the actual vehicle 100A.

Consequently, as the transmitting range, a substantially overall regionof the actual vehicle 100A can be covered. As a result, communication ofthe control apparatus 14 with the electronic key 12 can be performedwith certainty when the user gets on and operates the actual vehicle100A, when the user is running with the actual vehicle 100A, uponopening or closing operation of the seat 140 and when the electronic key12 is accommodated in the helmet accommodating space. In this instance,since the single transmitting antenna 72 may be installed, communicationof the control apparatus 14 with the electronic key 12 in all of thesituations described above can be achieved without inviting increase ofthe cost and the weight, increase of the installation space and soforth.

Further, a bag in which the electronic key 12 is placed is sometimesaccommodated in the helmet accommodating space provided under the seat140. Also in this instance, however, communication between the controlapparatus 14 and the electronic key 12 is performed with certainty.Consequently, a so-called shut-in state (a state wherein the seat 140cannot be unlocked while the electronic key 12 remains accommodated inthe helmet accommodating space) can be prevented.

In the electronic key system 10B according to the second embodiment, thetransmitting antenna 72 of the control apparatus 14 is installed on theseat 140 or the seat handle 144 of the actual vehicle 100B. Therefore,the request signal Sr transmitted from the control apparatus 14 isoutputted from the seat 140 or the seat handle 144. Consequently, as thetransmitting range, the seat 140 and a region around the seat 140 can becovered. As a result, communication of the control apparatus 14 with theelectronic key 12 can be performed with certainty even if the electronickey 12 is placed in the helmet accommodating space 142, and a so-calledshut-in state of a baggage or the like can be prevented.

Normally, the user operates the seat 140 to open or close standing onthe left side of the actual vehicle 100B. Therefore, by mounting thetransmitting antenna 72 on the left side face of the seat 140,communication of the control apparatus 14 with the electronic key 12upon an operation to open or close the seat 140 can be performed withcertainty.

Further, the seat handle 144 can normally be assembled later to thevehicle body of the actual vehicle 100B. Therefore, where thetransmitting antenna 72 or the starting switch 70 is provided on theseat handle 144, the shape of the vehicle body or the path of wiringlines need not be changed significantly in order to provide thetransmitting antenna 72 or the starting switch 70. In other words, thetransmitting antenna 72 or the starting switch 70 can be installed witha slight design change, and also the cost can be reduced advantageously.

Subsequently, the electronic key systems 10C, 10D according to a thirdembodiment and a fourth embodiment are described with reference to FIGS.13 to 15.

First, the electronic key system 10C according to the third embodimenthas a configuration substantially similar to that of the electronic keysystem 10A according to the first embodiment described above. However,the electronic key system 10C is different from the electronic keysystem 10A in that a transmitting unit 160 is installed in the proximityof the center of an actual vehicle 100C as shown in FIG. 13.

The electronic key system 10D according to the fourth embodiment has aconfiguration substantially similar to that of the electronic key system10A according to the first embodiment described above. However, theelectronic key system 10D is different from the electronic key system10A in that a transmitting unit 160 is installed on the seat 140 of theactual vehicle 100D or in the proximity of the seat 140 as shown in FIG.14.

In the transmitting unit 160, the transmitting circuit 46 is separatedfrom the control apparatus 14 formed from a system LSI so as to form asingle electronic part 162 as shown in FIG. 15. The electronic part 162is electrically connected to the transmitting antenna 72 so as togenerally form a unit.

Subsequently, the electronic key systems 10E, 10F according to a fifthembodiment and a sixth embodiment are described with reference to FIGS.16 to 18.

The electronic key system 10E according to the fifth embodiment has aconfiguration substantially similar to that of the electronic key system10A according to the first embodiment described above. However, theelectronic key system 10E is different from the electronic key system10A in that a transmitting/receiving unit 170 is installed in theproximity of the center of an actual vehicle 100E as shown in FIG. 16.

The electronic key system 10F according to the sixth embodiment has aconfiguration substantially similar to that of the electronic key system10A according to the first embodiment described above. However, theelectronic key system 10F is different from the electronic key system10A in that a transmitting/receiving unit 170 is installed on the seat140 of the actual vehicle 100F or in the proximity of the seat 140 asshown in FIG. 17.

In the transmitting/receiving unit 170, the receiving circuit 44 and thetransmitting circuit 46 are separated from the control apparatus 14formed from a system LSI to form a single electronic part 172. Thus, theelectronic part 172 includes the receiving circuit 44 and thetransmitting circuit 46 integrated therein as seen in FIG. 18. Thetransmitting circuit 46 of the electronic part 172 and the transmittingantenna 72 are electrically connected to each other so as to generallyform a unit.

Which one of the electronic key systems 10A to 10F according to thefirst to the sixth embodiments described above should be selectivelydetermined taking the size of the actual vehicles 100A to 100F, thepaths of the wiring lines, the installation space for the transmittingantenna 72 and so forth into consideration.

It is to be noted that the electronic key system for a vehicle accordingto the present invention is not limited to the embodiment describedabove but can adopt various configurations without departing from thesubject matter of the present invention.

1. An electronic key system for a vehicle, the electronic key systemcomprising a control apparatus mounted on the vehicle and an electronickey, wherein the control apparatus includes a transmitting antenna, theelectronic key permits transmission of a response signal in response toreceiving a request signal transmitted from said control apparatusthrough the transmitting antenna, and said transmitting antenna isinstalled in the proximity of the center of said vehicle.
 2. Anelectronic key system for a vehicle according to claim 1, wherein saidtransmitting antenna is installed at a position within a range from anupper portion of the vehicle to a lower portion of the vehicle, andwithin a range from a point at one fourth of a wheel base to anotherpoint at three fourths of the wheel base with reference to the center ofa front wheel of said vehicle.
 3. An electronic key system for a vehicleaccording to claim 1, wherein where said vehicle includes a seat onwhich a user is to be seated, said transmitting antenna is installed inthe proximity of a front portion of said seat.
 4. An electronic keysystem for a vehicle includes a control apparatus mounted on the vehicleand an electronic key, wherein the control apparatus comprises atransmitting antenna, the electronic key permits transmission of aresponse signal in response to receiving of a request signal transmittedfrom said control apparatus through the transmitting antenna, saidvehicle includes a seat which permits opening and closing movement and alocking apparatus for locking said seat to prevent opening of the seatuntil a unlocking instruction is supplied thereto; said controlapparatus includes a verifier which verifies the response signal and adriver which outputs an unlocking instruction to said locking apparatuswhen it is discriminated that the response signal is a request from alegal user; and said transmitting antenna is installed on said seat orin the proximity of said seat.
 5. An electronic key system for a vehicleaccording to claim 4, wherein said transmitting antenna is provided on aleft side face of said seat.
 6. An electronic key system for a vehicleaccording to claim 4, wherein the vehicle comprises a seat handle whichis used to manually open or close said seat, and is provided around arear portion of said seat, and said transmitting antenna is installed onsaid seat handle.
 7. An electronic key system for a vehicle, theelectronic key system comprising a control apparatus mounted on thevehicle and an electronic key, wherein the control apparatus includes atransmitting antenna, the electronic key permits transmission of aresponse signal in response to receiving a request signal transmittedfrom said control apparatus through the transmitting antenna, and saidtransmitting antenna is installed on the vehicle in a location whichprovides a transmission range which includes at least a space occupiedby a vehicle operator during vehicle use.
 8. The electronic key systemfor a vehicle of claim 7 wherein the transmitting antenna is installedon the vehicle in a location which provides a transmission rangeincluding the entire vehicle.
 9. The electronic key system for a vehicleof claim 7 wherein initiation of operation of the vehicle is permittedonly when the electronic key is within the transmission range, andwherein a warning is provided when the electronic key is moved out ofthe transmission range during operation of the vehicle.
 10. Theelectronic key system for a vehicle of claim 7 wherein the controlapparatus and the electronic key communicate at regular intervals duringoperation of the vehicle.
 11. The electronic key system for a vehicle ofclaim 10 wherein a warning is issued by the control apparatus ifcommunication between the control apparatus and the electronic key failsfor a predetermined length of time.
 12. The electronic key system for avehicle of claim 1 wherein said transmitting antenna is installed on thevehicle in a location which provides a transmission range including atleast a space occupied by a vehicle operator during vehicle use.
 13. Theelectronic key system for a vehicle of claim 1 wherein said transmittingantenna is installed on the vehicle in a location which provides atransmission range including at least a space occupied by a vehicleoperator during vehicle use, initiation of operation of the vehicle ispermitted only when the electronic key is within the transmission range,and a warning is provided when the electronic key is moved out of thetransmission range during operation.
 14. The electronic key system for avehicle of claim 1 wherein the control apparatus and the electronic keycommunicate at regular intervals during operation of the vehicle. 15.The electronic key system for a vehicle of claim 14 wherein a warning isissued by the control apparatus if communication between the controlapparatus and the electronic key fails for a predetermined length oftime.